LCD monitor failed displaying in Panasonic NV-GS5 B

Guest

The 2.5" LCD display Monitor in NV-GS5B stopped displaying. It's
completely black (like it is not turned on). First it still displayed image
when the LCD display was opened a bit, and when opened further it was black
again, but later it didn't display any image even when a little opened.
It's black all the time no matter in which position it is opened.
Please advise what happened and how can I fix it myself.
I tried the restart button once, but it didn't help.
Image in the Viefinder is displayed correctly when the LCD Monitor is closed.